Hardness Test Pencil

Coatings & Industry > Physical properties > Hardness

Hardness Test Pencil, Model 318For the Measuremenof the Hardness ofProtective CoatingsThe degree of hardnessof paint films, plastic coatings, etc. can be accuratelymeasured and recorded with the Hardness Test Pencil,Models 318 and 318 S, no matter whether on a level orcurved surface, small or large.The instrument is alwaysready for use and, because ofit’s small size easytransportable, an asset which will be appreciated by allconcerned with hardness tests.

The handling of the Hardness Test Pencil is extremelysimple.The estimated or known spring tension is set with thehelp of the slider. Holding the instrument upright and placingits point on the test surface one draws a 5 to 10 mm longline at a rate ofapproximately 10 mm/sec.The stylus shouldproduce a scratch which is just visible with the naked eye. Ifthe spring pressure is toohigh, the scratch is clearly visible;if too low, no scratch appears. The applied pressure, fixed bylocking the slider, is marked inNewtons

Gashes and mars are not nice to look at, especially not on smooth, shiny paint surfaces.

But they can occur quite quickly: fingernails can unintentionally scratch over a matt-polished table.

Or, a branch can grind across the beautiful paint of a Cadillac.

The mar is often from a small cause but can leave a big mess!

Metal marking is another type of mar. Here, the culprits are small metal particles of coins or similar which "rub off", thereby leaving ugly scratches on the surface.

Previously you could "inspect" a surface only with your fingernails.

Now for the first time, the Model 435 Mar tester enables you to specifically define the behaviour of coating surfaces with an exact test value.

Scars on surfaces are unsightly, especially on smooth, glossy surfaces. Surfaces can be ruined so easily - for example marks on the matt polished

surface of a table, by a fingernail, or on the shiny bodywork of a Cadillac, by a twig. Great annoyance can result from such small causes.

Marks can also be caused by metallic objects. The culprits may be metal particles from coins, cutlery or rings on fingers. Any of these can mar surface finishes.

The traditional test for the resistance of surfaces to such damage was to try to mark the surface with a fingernail. With the Mar Tester, Model 435, the quality of the surface can be measured accurately.

Design and Function

The scaring tool in the form of a disc, with locking facility, made of special plastic or metal, is mounted on a screw and is under pressure from a helical spring. This applies to a force which is adjustable from 0 to 20 N. The instrument is placed onto the surface so that it rests on the two guide wheels and the marking wheel which is locked in position then presses onto the surface with the pre-set force from the spring. The range of spring forces available is divided into three sections, each covered by one of three exchangeable springs:

Test range 1: 0 - 3 N - Sensitivity 0,1 N

Test range 2: 0 - 10 N - Sensitivity 0,5 N

Test range 3: 0 - 20 N - Sensitivity 1,0 N.

Note:

The test discs will wear at the point at which they are used. After 100 tests the discs should therefore be moved round so as to bring a point about 2 mm further along on the periphery into operation. The point at which the marking disc is first used should be marked by a scratch.

In principle, the Model 435 S is suitable for testing the adhesion of almost all printed scales, numbers, inscriptions and markings.

When used as an adhesion tester e.g. the colouredcoating applied to the dial of a speedometer in theshape of raised numbers, points or scale lines, istested concerning its adhesion to the substrate, bylateral slipping with a defined “blunt” test bodygeometry, with a preselected test force.

When used as a scratch resistance tester fortesting surfaces against “blunt” effects, it isrecommended for testing surfaces on which theHardness Test Rod 318 is still too “aggressive” –even using the largest tip diameter of 1 mm availablefor this purpose.

Design and Function

The scaring tool in the form of a disc, with lockingfacility, made of special plastic or metal, is mountedon a screw and is under pressure from a helicalspring. This applies to a force which is adjustablefrom 0 to 20 N. The instrument is placed onto thesurface so that it rests on the two guide wheels andthe marking wheel which is locked in position thenpresses onto the surface with the pre-set force fromthe spring. The range of spring forces available isdivided into three sections, each covered by one ofthree exchangeable springs:

Test range 1: 0 - 3 N - Sensitivity 0,1 N

Test range 2: 0 - 10 N - Sensitivity 0,5 N

Test range 3: 0 - 20 N - Sensitivity 1,0 N.

Note:

The test discs will wear at the point at which they areused. After 100 tests the discs should therefore bemoved round so as to bring a point about 2 mmfurther along on the periphery into operation. Thepoint at which the marking disc is first used should bemarked by a scratch.

Test head „C“ (movable/retrofit) for models 318/318 S, for using the Clemen test tip

Hadness Test Pencil

Order number: 101-2109.01.32Attention: Requires a Clemen test tip as well as a chucking adapter (rolling – for fixing and vertical guidance of the Hardness Test Pencil) and handle (anti-slip grip)

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Test tip acc. to Clemen (R 1.0 mm)

Hadness Test Pencil

Order number: 101-0218.02.32

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Special head (for use Model 318 in connection with film applicator COATMASTER 510)

Hadness Test Pencil

Order number: 101-0769.01.32

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Chucking adapter (rolling) for fixing and vertical guidance of the Hardness Test Pencil

Hadness Test Pencil

Order number: 101-1972.01.32

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Handle for the chucking adapter

Hadness Test Pencil

Order number: 101-1969.02.32 Handle for the chucking adapter adaptable anti-slip grip made of aluminium with engraved grid pattern, with freely rotating axis for constant force application. When using Model 318 C, the rotation function has to be locked. -